Multiblade fan construction



Oct. 26, 1937. CARY ET AL 2,097,205

MULT IBLADE FAN CONS TRUCT ION Filed June 16, 1936 3mm; [bgr/es Ho/Ieriib Beecher 5. [o

Sa em/m s Patented @ct. 26, 1937 UNITED STATES amt PATENT OFFICE Mich., assignors to Hayes Industries,

Inc.,

Jackson, Mich, a corporation of Michigan Application June 16, 1936, Serial No. 85,458

7 Claims. (01. 170-159 The present invention relates to improvements in multi-blade' fans of the propeller or screw type and is particularly concerned with those used in connection with a cooling system of an engine in an automotive vehicle.

Our invention is concerned with the economical manufacture of fans employing the principle of construction disclosed in U. S. Patent to Geise, No. 1,983,606, granted December ll, 1934, and is considered to be an improvement thereon.

As disclosed at length in the aforesaid patent, so-called fan noises have been materially reduced by spacing adjacent pairs of blades difl'erent from following adjacent pairs. Tests have shown us that the greatest reduction in noise over prior construction is'obtained with each blade of the fan spaced a different arcuate distance from each adjacent blade. Where a multi-blade fan is desired with each blade unequally spaced from its adjacent blades, the balancing of the same in production becomes a problem. In the copending application Serial No. 79,949, filed May 15, 1936 by Beecher B. Cary, one of the joint applicants in this application, the problem of balancing has been solved by associating two separate inherently balanced fan units into a single unitary fan construction.

By the present invention, the desired result has been obtained with a single unit which is placed in balance by the grouping of two or more blade parts of similar weight. and configuration to counterbalance the inherently unbalanced condition resulting from the unequal spacing of all the blades of the fan.

Thus it becomes the object of the invention to provide a fan of the character described in which blades of equal weight are so spaced and grouped as to provide a balanced unit.

Another object is to provide a fan construction having a central spider with radially disposed arms upon which the blades of the fan are supported in which the spacing of the blades is such that with blades of equal weight the unbalanced condition of the fan may be put in balance by associating an additional blade of identical construction upon one or more of the blades of the fan.

A furtherobject is to provide a fan having unequally spaced radially disposed blades of similar weight and construction, in which the center of mass of the unbalanced fan is such with reference I to one of the blades of the fan as to be moved to the axis of rotation by associating an additional blade of similar construction and weight with that particular blade.

In the accompanying drawing wherein a single embodiment of the invention is considered to be sumcient to clearly illustrate the principles of the invention,

Fig. 1 is a side elevational view ofthe fan supported for rotation upon a suitable hub,

Fig. 2 is a front elevational view of the fan construction shown in Fig. 1 removed from its supporting hub, and

Fig. 3 is a fragmentary exploded view of one of the blades of the fan shown in Fig. 2 showing the counterbalancing blade.

In the manufacture of parts of automotive vehicles the quantity produced is great and highly competitive with the result that, particularly with reference to the manufacture of fans, every possible economy in labor and material must be effected. In view of this situation the assembly 'of the fan must be simple and of a character re-- sulting in a unit balanced within the range of permitted tolerances. Reduction in cost of construction may also be obtained b y.reducing the number of different parts to a minimum particularly in the case of a sheet metal'construction in which spider l0 adapted to be suitably. supported on the hub l2 on the fan shaft in a well knownmanner.

'Radially disposed arms l4, l6, l8, and 20 umequally spaced about the center of rotation of the fan are deflected togive the desired pitch and carry the blades 22, 24, 26, and 28 which are riveted or otherwise suitably attached. The blades are preferably of sheet metal with the blades 22, 24, and 26 each made up of a single part while the blade 28 is made up of two sheet metal parts 30 and 32 superimposed upon each other and attached to the arm 20 in the same manner as the remaining blades. It is to be understood that preferably the single blades 22, 24, and 26 and the parts 30 and 32 making up the blade 28 are all stamped out on the same die and from stock of the same gauge. Also the spider I0 is preferably in balance and in the illustrated embodiment this is accomplished by making the arm 20 larger and longer than the remaining arms and by employing an additional rivet.

Without limiting the invention to a four bladed fan or to employing a single blade part for counterbalancing the unit as we contemplate constructions of five or more blades and the use of one or more counterbalancing blade parts superimposed upon one or more single blades of the fan, in one commercial form of the invention now being used the blades are spaced in the following manner: Blades 22 and 24 are spaced 42 11.5; blades 24 and 26 are spaced 76 22.3; blades 26 and 28 are spaced 112 22.7; and the blades 28 and 22 are spaced 129' 3.5. With this spacing arrangement of the blades 22, 24, and 26 which are of equal weight, the same are counterbalanced by the blade parts 30 and 32 which go to make up the two-ply blade 28.

From the foregoing description it will be apparent that the balanced fan consists of only two diiferent parts; the spider Ill and the blade parts 22, 24, 28, 30, and 32 all of which are identical except for the rivet holes in the parts 30 and 32. In addition the extra blade part 32 does not change thebppearance of the fan to any noticeable extent nor does it interfere with the air stream of the same as would known types of counterbalancers generally used in counterbalancing the out of balance forces of rotating bodies.

Having thus described ourinvention what we desire to protect by Letters Patent and claim is:

1. A multi-blade fan having a plurality of irregularly spaced single blade parts and an extra similar blade part acting as a counterbalance for the fan associated with one of said single blade parts, all of said blade parts being substantially identical in size, configuration, and gauge of material.

2. A multi-blade fan having a sheet metal central spider with radially disposed irregularly spaced arms, single blade parts carried by said arms, and an extra similar blade part acting as a counterbalance for the fan associated with one of said single blade parts, all of said blade parts being substantially identical in size, configuration, and gauge of material.

3. A multi-blade fan having a sheet metal central spider with irregularly spaced radial arms. bladeparts supported from said arms, the configuration of said spider and blade parts and the distribution of the mass thereof being such as'to dispose the center of mass of the fan to one side of the axis of rotation and diametrically opposite one of said blade parts and an extra similar blade part superimposed upon said last blade part and functioning to shift the center of mass of the fan to its axis of rotation to balance the same, I

all of said blade parts being substantially identical in size, configuration, and gauge of material.

4. A multi-blade fan having a central blade supporting structure, a plurality of similar single blade parts irregularly spaced about said structure, the center of mass of said structure with said blade parts attached being disposed to one side of the axis of rotation of the fan and substantially diametrically opposite one of said blade parts, and an extra blade part imposed upon said last blade part and functioning to shift the center of mass of the fan to the axis of rotation to balance the fan, all of said blade parts being substantially identical in size, configuration, and

gauge of material.

5. A multi-blade fan comprising a balanced central blade supporting structure,-a plurality of blades spaced about said structure, certain of said blades being of equal mass and similar configuration and being irregularly spaced with reference to one of said blades as to be counterbalanced as a group by said last blade when of twice the'mass of said certain blades, said last blade beixig constituted by two imposed blades each corresponding to said certain blades.

6. A multi-blade fan comprising a balanced central blade supporting structure, a plurality of similar'blade parts supported from said structure, two of said blade parts being imposed upon each other ,to provide'a two-ply blade, the remaining blade parts all being relatively spaced about said structure with reference to said two blade parts being such as to be balanced as a unit by said two-ply blade, all of said blade parts being substantially identical in size, configuration, and gauge of material. I

7. A four blade fan comprising a balanced central blade supporting structure, five blade parts substantially identical in'mass and configuration supported from said structure at equal distance from the center of rotation of the fan, two of said blade parts being imposed one upon the other to constitute a single blade while the remainder of said blade parts are separately place said fan in balance.

BEECHER B. CARY. CHARLES HOLLERITH.

ply blade part, the spacing of said remaining' 

